Add 1 cup of flour and mix until just combined. Repeat with the rest of the flour. Do not over-mix.

Add chocolate chips and/or walnuts to the mix.

Pour into prepared pan. Top with chocolate chips and bake about 35-45 minutes, until it’s browned on the top and a toothpick comes out only with slight crumbs (or clean). Cool at least 10 minutes before slicing.